Apparatus and Method for Retracting Brain Tissue During Brain Surgery

ABSTRACT

A method of performing brain surgery on a patient having a skull and brain tissue, that starts by creating an opening, having a rim, in the skull. The method uses an assembly for facilitating brain surgery that includes a curved frame, defining an inward dimension and an outward dimension; a plurality of spatula arm subassemblies, each including a spatula arm frame clamp, releasably attached to the frame, a spatula arm held and supported by the spatula arm frame clamp and a spatula extending from the inward end of the spatula arm of the spatula arm subassembly. The assembly is clamped to the rim and the spatula arms are positioned so that the spatulas engage the brain tissue in a manner that facilitates surgery.

RELATED APPLICATIONS

This application is a continuation of application U.S. Ser. No. 16/373,888, filed Apr. 3, 2019, which is incorporated by reference as if fully set forth herein.

BACKGROUND

A brain surgeon performing surgery through an opening created in the skull, is typically faced with the challenge of pushing brain tissue out of the way of a target surgical location and restraining the brain tissue during surgery. In many surgical situations, this is done by finding a natural cleft between the lobes, working a pair of spatulas into the cleft and then separating the spatulas to separate the brain tissue. To keep the tissue separated as the surgeon operates, the spatulas must be held in place. This is typically done by arms that are attached to some article that is held in constant position, relative to the patient's head. Most typically, the arms are attached to the clamp that is used to stabilize the patients head during surgery, but in some cases the arms are attached to the surgical table. One disadvantage of these arrangements is that a long arm is necessary to reach from its mount. It is difficult to obtain the desired stability with such a long arm, and it may even obstruct the freedom of movement of the brain surgeon.

SUMMARY

The following embodiments and aspects thereof are described and illustrated in conjunction with systems, tools and methods which are meant to be exemplary and illustrative, not limiting in scope. In various embodiments, one or more of the above-described problems have been reduced or eliminated, while other embodiments are directed to other improvements.

In one aspect, the present invention may take the form of a method of performing brain surgery on a patient having a skull and brain tissue, that starts by creating an opening, having a rim, in the skull. The method uses an assembly for facilitating brain surgery that includes a curved frame, defining an inward dimension and an outward dimension; a plurality of spatula arm subassemblies, each including a spatula arm frame clamp, releasably attached to the frame, a spatula arm held and supported by the spatula arm frame clamp and a spatula extending from the inward end of the spatula arm of the spatula arm subassembly. The assembly is clamped to the rim and the spatula arms are positioned so that the spatulas engage the brain tissue in a manner that facilitates surgery.

In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the drawings and by study of the following detailed descriptions.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments are illustrated in referenced drawings. It is intended that the embodiments and figures disclosed herein are to be considered illustrative rather than restrictive.

FIG. 1 shows an isometric view of a brain tissue retractor assembly, according to the present invention.

FIG. 2 shows an exploded perspective view of a spatula arm assembly, that forms a part of the brain tissue retractor assembly of FIG. 1.

FIG. 3 shows an exploded perspective view of a skull clamp arm assembly, that forms a part of the brain tissue retractor assembly of FIG. 1.

FIG. 4 shows a sectional view of a clamp arm lock, which forms a part of the skull clamp arm assembly of FIG. 3.

FIG. 5 shows a sectional view of a portion of the clamp arm assembly of FIG. 3, clamped to the frame of the brain tissue retractor assembly, of FIG. 1

FIG. 6 is a detail sectional view of a portion of the spatula arm assembly of FIG. 2.

FIG. 7 is a detail partial sectional view of a portion of the brain tissue retractor assembly of FIG. 1, clamped to skull bone and spreading apart brain tissue.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1, in a first preferred embodiment, a brain tissue retraction assembly 110 takes the form of a hinged circular frame 112, having a set of releasably attached clamp arm-subassemblies 114 and releasably attached spatula-arm-sub-assemblies 116. Frame 112 defines an interior or inner direction, meaning further to the interior of the frame, and an exterior or outer dimension, meaning away from the interior of the frame, or further outside of the frame. Frame 112 is divided into two semicircular pieces 112 a, hinged together by a pair of hinges 112 b, which can be each be locked into position by a frame wing bolt 112 c.

Referring to FIGS. 3 and 5, each clamp arm-sub-assembly 114 includes a clamp arm base 118, having a lock plate 118 a that is opposed to a dog 118 b, protruding up from a dog plate 118 c. If a portion of frame 112 is interposed between plate 118 a and dog 118 b and a wing bolt 118 d is tightened down, then frame 112 is held tightly between dog 118 b and plate 118 a. When wing bolt 118 d is loosened, frame 112 is released from pressure and base 118 may be moved about frame 112 or removed entirely. A clamp arm 120 is slidingly engaged in a through-hole 118 e in base block 118 f and may be locked in place by locking lever 118 g. In a preferred embodiment, frame 112 is semicircular in cross-section, so that the mutually opposed surfaces of member 118 a and dog 118 b fit conformally about from frame 112.

Each clamp arm terminates at its interior end in a clamp head 122, having a tongue 124 that is brought closer to clamp head by a bolt 126, threaded through a hole in clamp head 122 and then helically engaged in a threaded hold in tongue 124, to tighten tongue 124 and clamp head 122 about the rim of a hole created in the skull, thereby holding frame 112 in place. Bolt 126 is loosened to loosen tongue 124 and head 122 from about the skull, to permit removal of the clamp head 122 and of the overall retraction assembly 110. Also, tongue 124 can be rotated relative to head 122, before being tightened into place by bolt 126. In one embodiment, the upper surface of tongue 124 and the lower surface of head 122 have a coating of a biocompatible and resiliently deformable material, such as silicone, to conform to the upper and lower surfaces of the skull hole rim. it is notable, however, that restraining brain tissue cannot apply a great force against the skull hole rim, as brain tissue is soft and pliable. Accordingly, every element of assembly 110 may be made of lightweight material and in thicknesses that do not provide the strength that might be necessary in other applications, but that are thin enough so that assembly 110 has a mass of, in one embodiment, less than 100 grams.

Referring to FIGS. 2 and 6, each spatula arm subassembly 116 includes a spatula-arm-base 150, including a base block 150 a, and a clamping block 150 b that includes an upwardly projecting dog 150 c. A clamping wing bolt 150 d is engaged into a threaded opening, which draws clamping block 150 b towards base block 150 a, when turned in a first direction, thereby clamping blocks 150 a and 150 b about frame 112. When wing bolt 150 d is turned in the opposite direction, base 150 is loosened from frame 112, for movement along frame 112, or removal from frame 112. A spatula arm 154 is held in place between two vertically rotatably-ears 156, which are in turn held between two wings 158 of a mounting bracket 160. A locking wing bolt 162 is tightened to hold spatula arm 154 in place, so that it cannot be moved inwardly and outwardly, and to hold ears 156 in place by pressure from wings 158, so that ears 156 cannot be rotated vertically, which would thereby vertically rotate arm 154. In addition, bracket 160 is mounted to base 150 so that it can be horizontally rotated, thereby horizontally rotating arm 154. A locking ring 162 is rotatable and helically threaded engagement to a bolt 164, permitting ring 162 to be tightened down against base block 150 a, thereby locking bracket 160, and thereby arm 154, in place against horizontal rotation. A spatula 170 extends downwardly at the end of arm 154.

In an alternative preferred embodiment spatula arms that are deformable and that hold their shape after deformation are provided. These arms are deformed into position, holding spatulas to restrain the brain tissue.

Referring to FIGS. 1 and 7, to use assembly 110, clamp arm-sub-assemblies 114 are moved on frame 112 and each clamp arm 120 is moved relative its base 118, until clamp heads 122 are arranged about the rim 210 of a hole in the patient's skull, and sub-assemblies 114 and arms 120 are locked in place, and clamp heads 122 and tongues 124 are tightened about the rim 210, to hold assembly 110 in place. With spatula arms 154 in an upwardly tilting orientation, the spatula arm subassemblies 116 are arranged in placement on frame 112, so that spatulas 170 may be at a correct location and orientation when lowered into place. Spatula arms 154 are rotated horizontally so that each spatula 170 is oriented along a cleft in the brain tissue 212. Then (step not shown), while the brain tissue is gently manually retracted, spatula arms 154 are vertically rotated down to place spatulas 170 so that they will continue to restrain the brain tissue 210 (as shown) when it is no longer manually restrained. Spatulas 170, in one embodiment, are made of a thin sheet of metal, that is resiliently deformable. Other materials may be used.

In one preferred embodiment, frame 112 is 18 cm (7 in) across at the hinges, and 16 cm (6.5 in) across in the orthogonal dimension. The frame defines an interior round area, having a diameter of about 15.24 cm (6 in.), for an interior area of about 730 cm. In a preferred embodiment, frame 112 is made of stainless steel, as are the subassemblies.

While a number of exemplary aspects and embodiments have been discussed above, those possessed of skill in the art will recognize certain modifications, permutations, additions and sub-combinations thereof. It is therefore intended that the following appended claims and claims hereafter introduced are interpreted to include all such modifications, permutations, additions and sub-combinations as are within their true spirit and scope. 

1. A method of performing brain surgery on a patient having a skull and brain tissue, comprising: (a) creating an opening, having a rim, in said skull: (b) providing an assembly for facilitating brain surgery: (i) a curved frame, defining an inward dimension and an outward dimension; (ii) a plurality of spatula arm subassemblies, each including a spatula arm frame clamp, releasably attached to said frame, a spatula arm held and supported by said spatula arm frame clamp and a spatula extending from said inward end of said spatula arm of said spatula arm subassembly; (c) clamping said assembly to said rim; (d) positioning said spatula arms so that the spatulas engage said brain tissue in a manner that facilitates surgery.
 2. The method of claim 1, wherein adjusting said spatula arm sub-assemblies includes changing position of said spatula arm sub-assemblies on said frame.
 3. The method of claim 1, wherein said spatula arm is rigid and has a longitudinal dimension and said spatula arm frame-clamp permits adjustment of said position of said spatula arm along its longitudinal axis, relative to said spatula arm frame-clamp.
 4. The method of claim 3, wherein said spatula arm subassembly further includes pivot joints that permit vertical and horizontal location of said spatula arm.
 5. The method of claim 1, wherein said assembly further includes: (a) at least one clamp arm subassembly, attached to said frame, including: (i) a clamp arm frame clamp, releasably attached to said frame; (ii) a clamp arm having a longitudinal dimension, releasably held and supported by said clamp arm frame clamp, and adjustable in position relative to said frame clamp along said longitudinal dimension; (iii) a skull clamp, supported by said arm, and adapted to clamp onto said rim; and (b) wherein said clamp arm subassemblies are used to clamp said frame to said rim.
 6. The method of claim 1, wherein said spatula arm is flexible and holds its shape after being bent into a position, and wherein said each spatula arm is bent to position each said spatula to beneficially restrain brain tissue, to facilitate surgery.
 7. The method of claim 1, wherein said frame defines an interior area substantially larger than that defined by said opening in said skull.
 8. The method of claim 7, wherein said skull clamp includes a head and a tongue, extending downward from said head, and wherein said head defines a through hole, and wherein a bolt is engaged to said through hole and with said tongue, so that when said bolt is tightened said tongue is lifted toward said head, thereby clamping any interposed element between said tongue and said head.
 9. The method of claim 7, wherein said tongue is horizontally rotatable. 